Jan. 9,1850.] fletcher on dudley trilobites. 235 



January 9, 1850. 



The following communications were read : — 



1. Observations on Dudley Trilobites. By Thomas William 

 Fletcher, F.R.S., F.G.S., &c. 



Genus Lichas. 



The genus Lichas has received little attention from British palaeon- 

 tologists, and even Burmeister was compelled to omit any notice of 

 it from the want of characteristic specimens. In the hope of being 

 enabled to contribute some materials towards a more perfect know- 

 ledge of the genus, I am induced to offer to the Society a notice of 

 several undescribed species which have recently been found in the 

 Wenlock limestone of Dudley. 



1. Lichas Bucklandi, Milne-Edw., sp. Pl. XXVII. figs. 1-5 ; 

 and Pl. XXVII. bis, figs. 1, 1 a, & 1 6. 



Synonyms. — ^^ Trilobite de Dudley,'" Al. Brongniart, 1822, Crust. 



Foss. pl. 4. f. 9. 

 Peltura Bucklandi, Milne-Edw. Crust, v. iii. 345. pl. 34. f. 12. 

 Arges Anglicus, Beyrich, Untersuch. fiber Tril. 2^^ St. t. 1. f. 3. 



This trilobite was first named by Prof. Milne-Edwards. Its ce- 

 phalic shield is figured by Dr. Beyrich from a Dudley specimen. 

 M. Brongniart, in his ' Histoire naturelle des Crustace's fossiles,' had 

 previously given, under the name of " a Trilobite from Dudley," a 

 figure of the under surface from a drawing by Mr. Stokes ; merely 

 remarking that the addition of spines to the tail, and the form of the 

 cephalic shield, appeared to indicate a species diifering from Calymene 

 Blumenbachii. 



The general form of the present species is oval and depressed ; its 

 length is about an inch and a quarter, and its width three-quarters of 

 an inch ; the length of the thorax exceeds that of the cephalic shield 

 and tail, which are about equal, the axis or middle division being 

 narrower than the lateral portions. Large tubercles cover the ce- 

 phalic shield, which is less than a semicircle, and is deeply indented 

 at the sides by the production of the front. The glabella is large, 

 broad, widest below, and divided into five tumid lobes ; the forehead 

 lobe is linear, and separated by deep curved sulcations from the short, 

 ovate, upper lateral lobes, which are of about equal width with it ; 

 these are smaller than the lower lateral lobes, which project consider- 

 ably below them. No basal lobes are visible in this species. The 

 neck lobe is prominent and broadest in the middle, and the neck furrow 

 distinct. Eyes forward, small, and prominent, placed beneath the la- 

 teral indentation of the head, close to the lower lateral lobe of the gla- 

 bella (Pl. XXVII. bis, fig. 1 b). Front margin narrow, the part above 

 the indentation being angular. Facial suture running immediately 

 beneath the front margin, and curving downwards to the eye, parallel 

 with the upper part of the glabella, below the eye curving outwards. 



